Recently, on-line distribution of music contents employing a network, such as Internet or cable television, has come to be put to practical application.
If, in this distribution system for music contents, the contents distributors distribute the musical contents over the network, on e.g., the Web. The user exploiting this music distribution system uses his or her own personal computer to access the Web furnished by the contents distributor to download the desired music contents.
Meanwhile, in this music distribution system, the downloaded music contents are made payable over e.g., a network.
However, if once the data in a personal computer owned by a user is destroyed, the music contents, once purchased, are lost. So, for restoring the music contents, the contents need to be purchased again.